The specific aim of this research is to conduct a longitudinal comparative study of the ways in which social networks and social support systems (informal network) inhibit, moderate, or facilitate the utilization of health care and social services (formal network) among elderly Mexican-Americans and non-Hispanic whites, by examining: the role of family, friends and other community networks; institutional and cultural barriers; knowledge and information about health care and social services; and need for health care and social services, among a population varying in levels of acculturation and socioeconomic status (SES), as well as differences in age cohorts and gender. The overall purpose of this research is to examine how social networks and social supports enhance the functioning and independence of the elder to maintain him/her in the community. A community-based comparative three-wave panel survey of the use of informal and formal networks and how they change over time as individual need changes among the older Mexican American population of Los Angeles County is proposed. Approximately 1000 respondents (700 Mexican-Americans and 300 non-Hispanic whites) aged 65+ will be interviewed face-to-face at three intervals, approximately one year apart. Interviews will encompass the following domains: contextual (acculturation, SES, gender, age, and other background variables), service indicators (need for health care and social services, knowledge and information, barriers), moderators (social networks and social support) and utilization and outcome (health care and social service use). The overall research methodology will employ a blended methodology of focus groups, structured interviews, and case studies. Data analysis is directed at both descriptive and explanatory objectives. Descriptive analyses include: frequency distributions and transformations to improve these distributions as necessary; comparisons of sample characteristics to those of population to assess representation; calculation of levels of key variables for the entire sample and the sub- groups etc. Explanatory analyses will include confirmatory factor analysis, latent variable causal models and stratified causal and linear models.